Automatic air-brake



(No Model.) 3 Sheets-Sheet 1. G. W. MARSH.

AUTOMATIC AIR BRAKE.

No. 396,284.- Patented Jan. '15, 1889.

m /l/ Ac m m u* f E els "7 "TX d] HH-" A; m

M *l l I N. 8 d I g1 4m R* c: Q V

:Y H /Q/ g;

t'- I Y t/J-J Mame/Mo@ o MM' l r6 (No Model.) 3 Sheets-Sheet 2.

G. W. MARSH.

AUTOMATIC AIR BRAKE. No. 396,284. Patented Jan. 15, 1889.

(No Model.) 3 Sheets-Sheet 3.

G. W. MARSH.

AUTOMATlC AIR BRAKE.

No. 396,284. .Patented Jan. 15, 1889. l

n. PETERS, vnuwumogaphr. wmingm n. c.

UNiTED STATESv PATENT Ormes.

GEORGE IV. MARSH, OF OAKLAND, CALIFORNIA.

AUTOMATIC AIR-BRAKE.

SPECIFICATION forming part of Letters Patent No. 396,284, dated January 15, 1889.

Applatml filed August l, 1888. Serial No. 281,708. (No model.)

To all whom t may concern: i

Be it known that I, GEORGE IV. MARSH, of the city of Oakland, Alameda county, State of California, have invented an Improvement in Automatic Air-Brakes; and I hereby declare the following to be a full, clear, and exact description of the same.

My invention relates to an improvement in that class of air-brakes for cars usually known as the IVestiiighouse automatic.

My invention consists, in'connection with the piston-valve and the sliding valve carried thereby, of a spring arranged to throw the valves back when the pressure within the auxiliary reservoir equals that in front of the piston-valve and of an exhaust-port which is opened by the slide-valve when thus thrown back, so that the brakes shall be relieved only after the auxiliary reservoir shall have been supplied.

In order to understand my improvement and its object, it will be necessary for me to describe particularly and in detail the present construction and operation of the Testiiigliouse automatic air-brake.

Referring to the accompanying drawings for a more complete explanation of my invention, Figure 1 is a view showing the brakecylinder in section and the auxiliary reservoir and valve-chest in elevation. Fig. 2 is avertical section of valve-chest and reservoir. Fig. 23 is an enlarged view of same, showing the parts in position so that the auxiliary reservoir is receiving air, the brakes being not yet relieved, as the exhaust-port c is cut off by cock L of Fig. il. Fig. I is a horizontal section of same on line .r x, Fig. 3. Fig. 5 is a vertical section similar to Fig. 3, the parts being in position to relieve the brake by the exhaust of air through my new port c2. Fig. 6 is a horizontal section of same on line y y, Fig. 5. Fig. 7 is a view of the under side of the slidevalve E.

F is the rotary release or cut-out valve, having a port, f, communicating at one end with the passage a through the auxiliary reservoir, and which leads to the brake-cylinder. The rotary valve F has also port f', which communicates with the train-pipe G and with the passage H, leading in front of the pistonvalve. In the valve chest or chamber C is made a port, c, and an exhaust-port, c. The port c communicates with the port f of the rotary valve F, and also with the port e of the slide-valve E, which said port e is of an elongated shape and is adapted to Join ports c and c of the valve-chainber. In the forward ring or packing-seat of the valve-chamber is made agroove, I, which communicates with a groove, t', made on the face of the pistonvalve, whereby an inlet is afforded for the air into the auxiliary reservoir.

The operation of the device thus briefly described is as follows: It will be understood that, this being an automatic air-brake, the brakes are set up against the wheels by the air in the brake-cylinder and are relieved by the escape of said air, which escape is due to mechanism operated by forcing an1 into the train-pipe. The air in the train-pipe passes in through the port f of the rotary v alve F and through the passage H, and, entering before the piston-valve D, forces said valve to its seat. This movement of the valve carries the slide-valve E with it, causing its port c to join the ports c c of the valve-chest, so that the air in the brakefcylinder escapes from said cylinder through the passage a, through the port f of the rotary valve F, throughthe port c of the valve-chest., port e of the slidevalve, and exhaust-port c of the valve-chest, thus exhausting and relieving the pressure in the brake-cylinder, so that the brakes are at once relieved. t

Vhen the pressure in the train-pipe is relieved, the air in the auxiliary reservoir A forces the piston-valve D backward, Which carries the slide-valve with it and cuts off the exhaust c', bringing another port, c', which is in said slide-valve, into communication with the port c of the valve-chest, so that the air from said reservoir passes through said ports and through portf and passage a into the IOO brake-cylinder, whereby the brakes are again applied.

The air is supplied to the auxiliary reservoir when the pressure is applied in the train-pipe to relieve the brakes, as described, said air passing through the train-pipe into the space in front of the piston-valve to force said valve to its seat, aportion of the air passing through the grooves I if in the packing-seat and in the face of the valve D into the auxiliary reser voir.

This is briefly the construction and mode of operation of the present automatic airbrake.

The grooves I and if, by which the auxiliary reservoir A is supplied with air, have necessarily to be small, so as to avoid too great an expenditure of the pressure in the train-pipe, which has to do its work upon a g'reat number of Valves throughout the train, and therefore but a small portion of air can be taken to supply the auxiliary reservoir. As a consequence, the brakes are relieved before the auxiliary reservoir is supplied, and if it be required to set the brakes again instantly, by relieving the air in the train-pipe, itis obvious that the auxiliary reservoir, being only partially supplied, can only partially apply the brakes. On grades, therefore, there is sufficient time for the car to get started and run away before the auxiliary reservoir is sufficiently supplied with air to apply the brakes. It is the object of my improvement to fully supply the auxiliaryreservoir before allowing the brakes to be relieved, so that if it be necessary to instantly apply them there will be sufficient pressure of air in the reservoir to accomplish this.

In the valve-eh est C, I make a supplementary exhaust-port, c?, which in this instance is just to one side of and between the ports c and c', and by an offset, c2, in the valve E, and which communicates with the port c in said valve, I provide for the communication with the supplementaryport c2 at the propertime. The port e is made of the shape shown either originally or by placing in the valves n ow in use the block e3, which cuts off port e2 when the slide-valve is forward.

To the inner end of the valve chest is screwed a cap, J, in which is titted a spring,

j, and the stem r, of the inner valve, K, the

forward end of which presses against the inner end of the slide-valve E, its face fitting against the face-plate d of the inner end of the stem (l of the piston-valve D. The sprin g tends to force the pistornvalve I) forward away from its seat. On the outside of the valve-chest I secure a petcock, I., by which I can eut off the regular exhaust-port c. Now, supposing this exhaust-port to bc cut off by the petcock and the pressure applied in the train-pipe, the first effect of this pressure is to force the piston-valve D to its seat, as before; but by reason of the exhaust-port c being cut off by the petcock the air from the brake cylinder is not allowed to exhaust through said port, as it does at present, nor can it exhaust through the new port c2, for the block c3 in the port e of the sl-ide-valve covers said new exhaust-port while the pistou-valve is at its seat. The air therefore first passes through the grooves I and i', heretofore described, into the auxiliary reservoir. As soon as the pressure in this reservoir equals the pressure in front of the piston -valve, the springj throws said valve and the slidevalve E forward. This forward movement of the valve It brings the offset e2 of the port e of the slide-valve into communication with the supplementary exhaust-port c2 in the \\'alve-chest,whereupon the air from the brakecylinder exhausts through said port and the brakes are relieved, as before; but it will be seen that this is not done until the auxiliary reservoir is supplied. The inner valve, l, when the spring' throws it forward, as just described, comes to a seat on the inner end of the valve-chest, so that the air can continue to pass into the auxiliary reservoir only through the small groove d2 in the faceplate d on the inner end of the stein d of the valve and through port 71'. in the inner valve and port, j', of the cap J. Provision is thus made for avoidin an expenditure of too great a proportion of the air in the trainpipe,which would otherwise pass too freely into the auxiliary reservoir.

This improvement need only be used on grades, as it is there only that the necessity arises for applying the brakes again before the auxiliary reservoir can be supplied. On a level the regular exhaust-port c can be used by opening the petcock Ii.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. In the automatic air-brake herein described, having theauxiliary reservoir, the brake-cylinder, the train-pipe connection, and the valve chest or chamber, with its grooved piston-valve, ported slide-valve, and port c, the spring j, for throwing the valves back when the pressure within the auxiliary reservoir equals the pressure in front of the piston-valve, and the exhaust-port c2 in the valve-chest, which is opened by the ported slide-valve when thrown back, substantially as and for the purpose herein described.

2. In the automatic air-brake lherein described, having the auxiliary reservoir, the brake-cylinder, the train-pipe connection, and the valve chest or chamber, with its grooved piston-valve, ported slide-valve, and port c, the ported inner valve bearing against the inner end of the slide-valve and the grooved inner end of the stem of the pistonvalve, the spring acting against said inner valve for causing it to move forward to its seat and throw the piston-valve and slidevalve back when the pressure within the auxn iliary reservoir equals the pressure in front of the piston-valve, and the exhaust-port c2 in the valve-chest, which is opened by the IOO ported slide-Valve When thrown back, substantially as herein described.

3. In the automatic air-brake herein described, having the auxiliary reservoir, the brake -cylinder, the train-pipe connection, and the valve chest or chamber, with its grooved piston-Valve, ported slide-valve, and port c, the ported cap on the inner end of the Valve-chest, the ported inn er Valve Within said cap and bearing against the end of the slidevalve and the grooved inner end of the stein of the piston-Valve, the spring Within the cap and' acting against the inner valve for causing it to move forward to its seat and throw the piston-Valve and slide-Valve back when the pressure Within the auxiliary reservoir equals the pressure in front of the pistonvalve, and the exhaust-port c2 in the valvechest, which is opened by the ported slide- Valve When thrown back, substantially as and for the purpose herein described.

inentary exhaust-port c2 in the valve-chest,

which is opened by the ported slide-Valve when thrown back, substantially as herein described.

In Witness `whereof. I have hereunto set my hand.

GEORGE IV. MARSH.

fitnessesz S. H. NoURsE, H. C. LEE. 

